Developer for diazotype materials



Patented Oct. 27, 1953 UNITED STATES DEVELOPER FOR DIAZOTYPE MATERIALS Franciscus Antonius Hubertus Kessels, Venlo, Netherlands, assignor to Chemische Fabriek L. van der Grinten, Venlo, Netherlands, a partnership of the Netherlands No Drawing. Application May 28, 1952, Serial 12 Claims.

The invention relates to a developer for diazotype printing materials referred to hereinafter as a "diazotype developer. By this expression is to be understood a mixture (either a dry mixture to be dissolved, or a solution) containing as essential constituents one or more azo dyestuff coupling components and one or more potassium and/ or sodium salts of weak acids, such as carbonic acid, boric acid, formic acid, acetic acid, benzoic acid, tartaric acid and citric acid. Azo dyestuii components of good coupling activity are used and the alkali salts are so chosen that, in the slight excess used, they ensure sufficient azo dyestuff coupling between the azo dyestufi coupling components and the diazo compound used in the diazotype image the unexposed areas of which containa para-amino-diazo-benzene compound, with the usual quantities of acid con stituents. Azo dyestuff components of good coupling activity are, for example S-naphthol, the [i hydroxy-ethyl amide of Z-hydroxy-B-naphthoic acid, phloroglucinol, and resorcinol; an azo dyestuff component of insufficient coupling activity In the Netherlands June 16,

is, forexample, 2:3-dihydroxy-naphthalene-6- sulphonic acid. Diazotype developers are applied practically exclusively in such a manner that their aqueous solution is applied on the diazotype copy in-a layer of, for example, 8 to 12 g./so metre. tioned essential constituents, diaaotype develop ers generally also contain substances such as thiourea, alkali thiosulphate, wetting agents, aliphatic polyhydroxy compounds and the like. Diazotype developers with borates are to be preferred to those withcarbonates. Diazotype developersthat have to serve for the development of diazotype copies in which the diazo compound is a para-alkylamino-diazobenzene usually have a pH above .7; those used for diazotype copies containing para-acylamino-diazo-benzene compounds may have a pH alittle below 7,.while their concentration of buffer salts, such as formates, benzoates, and the'like is generally higher.

. According to the present invention diazotype' developers ,contain optical bleaching agents known per se (of. for example Netherlandspatent specification No. 55,370). By the use of such developers there is obtained an improvement in In addition to the above-mencount of their absorbing power for light of short wave lengths, they cannot be used in the lightsensitive diazotype layersin contrast to their inclusion in photographic layers according to French patent specification No. B78,823--with out impairing the lightsensitivity of the layers. Interfering reactions between the optical bleaching agents and the diazo compounds also frequently take place.

The diazotype developers according to the in vention contain as optical bleaching agent a blue-fluorescent salt of a p.p-diaminostilbeneo.o-disulphonic acid with one or more 1.3.5- triazine rings attached to the amino groups. This type of optical bleaching agent'with at least one triazine ring was found to be more suitable for the above-mentioned application in diazotype developers and to have a greater or more lasting effect than optical bleaching agents without a triazine ring derived from p.p-diaminostilbene-o.o'-disulphonic acid (of. for example French patent specification No. 878,155).

Examples of optical bleaching agents: used according to the invention are:

in which R1, R2, R3 and R4 stand for amino or aliphatically or aromatically substituted amino groups. Particularly good results are obtained with compounds in which the substituents R1, R2, R3 and R4 are amino groups at least one of which is aromatically substituted, and even better results when one or more of these aromatical ly substituted amino groups have a sulphonic acid or a carboxyl group attached to the arc matic radicle. Many of these can be dissolved in aqueous diazotype developers without any previous treatment. Less soluble optical bleaching agents of the type preferred for the invention may be finely distributed or emulsified in the aqueous developer.

The eiiect of the addition of the aforesaid optical bleaching agents to diazotype developers is that, in the diazotype copies produced therewith, the areas of the image contrast better with the exposed background. The results are most striking when the exposed background contains matter having a yellow or brown tint,

such as the azo. component B-hydroxy-ethyl amide of 2-hydroxy-naphthalene3-carboxylic acid, the photochemical decomposition product of a diam-compound, a stabiliser such as, for example, naphthalene-1.3.6-trisulphonic acid, and also when the diazotype copies begin to show the familiar discolouration uponageingi It has .3 also bee'n'found thattheeopticalbleaching agents, appliedto the diazotype copy via the diazotype developer, reduce the discolouration of the copy in daylight, a result which is particularly valu+ able when the diazotype copy-ie-ex-posedto light that is relatively rich in rays of short" wave lengths. Diazotype copies on colouredfibases; for? example buff, blue, green or red paper; also have a finer appearance when dveloped with'a dia'zo type developer according to the invention.

The following are representative diazotype. ma-

terials that can be developed withtheidiazotype'f developers of this invention.

A developer suitable for the development of diazotype paper B is composed as follows:

Diaeotype paper A Base paper of l lO-gt/sql metre is coated-with about 8=g./sq. metre of the followingisolutionuin water:

Para-diazo ethyl benzyl aniline nitrate 1.6%- Potash alum l Thiourea 2%= Ammonium oxalate 2%" Gelatin ".1

and dried, V

Diazotypei paper 8 Base papie'r of"80 gi/s'q metre-' is coated with about 12 g./sq. metre of the following solution Acopy on the diazotype materiaLBisdeveloped by the applicationof. aboutlOg/sq. metre. of the above developer. Adark brownicopy-is'obta-ined in which. the darlebrown-z dyestuff. is in J high con! trastwith the. clear white. ground. If the optical bleaching agent had been omitted iromlthe: composition of the developer, a copy would haveibeen obtained with: a somewhat dingy: background, with whichthe imageiwould contrast considerably 7 less.

EXAIVLPLE' 2-:

A; developer suitable for the development-of diaz otype paper Alis composed asfollows: N

in water: 40 Para-dia'zo-diethyl"0ltl'Ioch10r0ani1ine;Zll'fc chlo- -1Ourea T 33 Phloroglucmol g 6.5 Ilde double salt 3 Resorcinol 6 5 TaItBlliC al'cld 1.5% U '7 so Sodiumsalt of naphthalene-1.3 36 trisu1phonic lgl? lfic g id of lsopropyl naphthalene g 2 acid Sugar ::::::::::::::::g: ifi s f f Potassium tetraborate p entahydrate g '80 e a Potassium carbonate g 20 and dried. Optical bleaching agent. g 1

C'bHr-N'EF-C C-NH--CH=G.H Nib-GOSH l l. a

\ I \G NHI OzNs SO;Na

Didzotype paper C" Water a .1000

Ba's'e papen 01?. 110 gi/squmet're iscoated with about 10 g./sq. metre of the followingsolution'in waters v and dried.

The following examples will-serve to illustrate the invention, but arenotto bere'garded as limit- V ing it in any Way:

A- copy on diazoty-pe material A. is developed by the application of. about? 1-01" g./'sq. metre of the above developer. A: black copy isiobtained in which. the-'dyestufi is in strong contrastwith' the clear white ground. agent had been omitted: from the composition of the developer, a copy: would have been obtained with a: somewhat dingy background", with which the image would contrast considerably less strongly;

EXAMPLE 3 Thiourea' V g' If the optical bleaching 5 Phloroglucinol g 3 Sodium mono-2-ethyl-hexyl sulphate g 2 Benzoic acid g 2.5 Sodium benzoate g 14.3 Sodium formate g 6 the clear white ground. I1 the optical bleaching agent had been omitted from the composition of the developer, a copy would have been obtained with a somewhat dingy background, with which 146 5 the image would contrast considerably less Optical bleaching agent g 1 strongly.

/N N\ NH-o fi-NHOOH=CHONH-O l e-NH, N N A N SCnNa \C/ OzNa B Na \C/ 11TH: BITE:

Water g 1000 EXAMPLE A copy on diazotype material C is developed by the application of about g./sq. metre of the above developer. A brownish-black copy is obtained in which the brownish-black dyestuff is in high contrast with the clear white ground. If the optical bleaching agent had been omitted from the composition of the developer, a copy would have been obtained with a somewhat dingy background, with which the image would contrast considerably less.

EXAMPLE 4 A developer suitable for the development of diazotype paper A is composed as follows:

A developer suitable for the development 01 diazotype paper C is composed as follows:

In this there are dispersed 5 gfof the optical bleaching agent:

HOGQL /N\ /N\ CzHaOH /N(ll ("JNH oH=cHC -m1 110cm. N N N 1 cmion OzNe S0;Na v v N C a CH: OH: H, 47H: CH) H: on H H H Thiourea g; 20 p A DX n azotype material C is developed by Sodium thiosulphate g 50 e ppl tlon of about 10 g/sq. metre of the fimaphthol "g" 15 above developer. A brownish-black copy is oh- I l 5o tained in which the brownish-black dyestufi is in g of lsopropyl naphthalene Sm 3 strong contrast with the clearwhite ground. If 2 ac "i "f" the optical bleaching agent had been omitted Tr mm D 05p a e from the composition of the developer copy sodaFsh anhydrous 20 would have been obtained with a somewhat dingy Caffeme 5; ground, with which the image would contr considerably less.

H0 C=H4NH-G I N \O/ OgNa dome NH NH SOIH 0311 Water g- 1000' What I claim is:

A copy on diazotype material A is developed by the application of about 10 g./sq. metre of the above developer. A brown copy is obtained, in

which the brown dyestuii is in high contrast with 7 1. A developer for diazotype printing materials comprising at least one azo dyestuffco'upling component, at least one alkaline metal salt 'of a weak acid and a small amount of a salt of a blueenemas) :sulphonic acid compound containing one 1:315- triazine ring attached to each amino group and having the formula l N. N

comprising at least one azo dyestufi coupling co ponent. a eas one kalin m tali alt: of: a weak acidand a p p-diaminostilbene-o.o di sulphonic acid compound" containing one 1-:5; triazine ring attached to. each, amino group; and having the formula: l

in which at least one of R1, R2, R3 and R4 is an aromatically substituted amino group, at least one member of R1, R2 R3 and is analiphat;

V oaNa AOiNa fin which R1, R2, R3 and R4 are amino groups 3. A developer for diazotype printingmaterials {comprising at least one azo dyestufii coupling cpmponent, at least one alkaline metal salt or" a weak acid and a pp-diaminostilbene-o.o'-disulphonic. acid compound containing one 1 :3 5- t'riazine ring attached to each amino group and having the formula:

in which at least one member of R1, R2, R3 and R4 is an aliphatically substituted amino group and members of R1, R2, R3 and R are amino groups 6; A developer for diazotype printing materials comprising at least one azo dyestufi coupling 30 component, at least one alkaline metal salt of a weak acidand a p.pediaminostilbene-omedisulphonic acid compoundcontaining one 1:-3:5'-tri- C l R:

azine ring attached to each amino group and having theformula:

N N 11 -0 CNEL 011:011 NH-C 0-11, I t t l OaNB some a p any remaining members of R1, R2; Raand R4 are 50 aminolgroups. v 4 a 4..- A developer f or diazot-ype printing materials comprising at least: one azo dyestu-ff coupling component, at: least one alkalinemetal salt of a weak acid: and a pipadiaminostilbeneaoo ditriazine ring attached to each amino-4 group. and having the formula:

in which at least one member of R1, R2, and R4 is an aromatically substituted amino group and any em inine m m sof R1, Rafts and 34am ,5 Qg oun a A d vel per for diazo ype-pr ingma er al sulphonic acid compound containing one 123:5

' II I N OaNa sloaNa 0 a in which R1 and R3 are hydroxy ethyl amino up and 2: and. 4 rep nt 'rihe i' amino groups which are substitutedby a siJlphonic acid group.

' 7*. A developer for diazotype printing mate fals comprising at least one azo dyestufi coupling component, at least one alkaline metal salt of a Weak acidand a p;p-diaminostilbene-o.o" cli sulphonic acid compound containing one 123:5-

triazine ring attached to each amino group and having the formula: r

, r g; in which-R1 and R3 arephenylamino groups and R2 and R4 are phenylamino groups. which are substituted by a sulphoni a d rou icallysulostituted amino group and any remaining 7 in which R1, R2, R3 and R4 are di(hydroxyethyl) amino groups.

9. A developer as claimed in claim 4 in which at least one of the aromatic substitutents carries a sulphonic acid group as a substituent.

10. A developer as claimed in claim 4 in which at least one of the aromatic substituents carries a oarboxylic acid group as a substituent.

11. A process for developing light sensitive sheet material which, at least in the unexposed condition, contains a diazo compound as the light sensitive material comprising applying to the said 110 sheet material a thin film layer of a developer as claimed in claim 1.

12. A process as claimed in claim 1.1 in which the light sensitive sheet material is diazotype paper.

FRANCISCUS ANTONIUS HUBERTUS KESSELS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,589,519 Hoch Mar. 18, 1952 2,612,501 Wilson Sept. 30, 1952 FOREIGN PATENTS Number Country Date 624,052 Great Britain May 26, 1949 878,823 France Nov. 2, 1942 993,648 France July 25, 1951 55,370 Netherlands Sept. 16, 1943 

1. A DEVELOPER FOR DIAZOTYPE PRINTING MATERIALS COMPRISING AT LEAST ONE AZO DYESTUFF COUPLING COMPONENT, AT LEAST ONE ALKALINE METAL SALT OF A WEAK ACID AND A SMALL AMOUNT OF A SALT OF A BLUEFLUORESCENT P.P''-DIAMINOSTILBENE 0.0"DISULPHONIC ACID IN WHICH AT LEAST ONE OF THE AMINO GROUPS CARRIES A 1:3:5-TRIAZINE RING. 